Railway-traffic-controlling apparatus



Aug. 30, .1927.

R. A. McCANN RAILWAY TRAFFIC CONTROLLING APPARATUS Filed July 29. 1926 DmWbrz'dye A 1, C 5 1? l I 1 2 R g 11 i 6 X $1 14/ 15 If? 9 g? 7 INVENTO I vii -W Patented I 3 UNITED STATES RONALD A. MOCANN, OF SEVISSVALE, PENNSYLVANIA, ASSIGNOR TO THE UNION VALE PENNSYLVANIA, A CORPORATION OF SWITCH 6a SIGNAL COMPANY,-OF 'SVIISS PENNSYLVANIA.

PATENT oFFrcs.

RAILWAY-TBA ?FIG-CONTROLLING APPARATUS.

Application filed July 29, 1926. Serial No. 125,764.

My invention relates to railway tra'liiccontrolling apparatus, and particularly to apparatus of the type wherein train carried governing mechanism is controlled by energy 'traclrway portion of such apparatus.

I will describe one form ofapparatusembodying my invcntioin'and will then point out the novelifeatures thereofin claims.

The accompanying drawing is a diagrammatic view showing one from of apparatus embodying my invention.

Referring to the drawing,the'reference characters l and l designate the track rails of a railway. along which tratlic normally moves in the direction. indicated by the arrow. These rails are divided by insulated joints 2 into a plurality of track sections, of which only one complete section A B is shown in the drawing. Located at an intermediate point in this section is a drawbridge C, which controls a contact 13 in such manner that the contact is closed when the drawbridge is closed and locked, but is open when the drawbridge is open or unlocked. v

Alternating track circuit current is supplied to the rails of section A-B by a trans former T the secondary of which is constantly connected across the rails adjacent the point B, and the primaryof which is' constantly supplied with alternating current from a source which is not shown inthe drawing. v

Means are also provided for supplying the section with train governing current which flows through the rails ofthe section in multiple, and which I will hereinafter term loop current. F or this purpose an impedance 3 is connected across the rails of the section adjacent the point A, a second impedance is connected acrossthe rails imn'iediately in advance of the drawbridge C, and a third impedance 5 is connected across the rails adjacent the pointB. Train governing current is supplied by a transformer L the primary of which is constantly connected withthe same sourceof alternating current as that which supplied the primary of transformer T The rela' tive polarity of the train governing current is controlled by track relay R for the section neiiit in advai'ic'e of the point When tracir i. R is energized, and the draw throughout the entire length of this bridge C is closed and locked, train gov erning current flows from the right-hand terminal of the secondary of transformer L through front contact 6 of track relay L3 to, the mid-point of impedance 5 and then through the rails 1 and 1 in multiple to impedance 4i, and from theinid-point of this impedance, through wire 14, contact 18, wire" -12', windin0 of a relay X, wire 8,kand front contact .7 or relay R to'the left-hand termireal of the secondary of transformer L hen relay R is de-energized, the circuit for; the train governing current is the same, but the relative'polarity of the current with respect to the track circuit currentis reversed because of thepole-changing'action of contacts 6 and 7 of relay-R 'When contact 13 is open, relay X is deenergized, whereupon back contact of this relay connects wire 8 with the mid-point of the second impedance 4:. The traingoverning circuit is then fronithe right-hand terminal of the secondary of transformer L through front contact 6 of relay R to the mid-point of impedance 5, then through the rails 1 and 1 inimult-iple to impedance 4, and from the mid-point of this impedance through wire 11, back contact 10 of relay X, wires 9 and'S, and front contact 7 of relay R to the left-hand terminal of the sec-" cupies a portion of track which issuppliedj with train governing current of normal relative polarity and with track circuit current, a caution lndication 1s given aboard the train when the track is supplied with train governing current of reverse relative polarity and with track circuit current, whereas astop indication is given aboard the train when the supply of either train governing current or track circuit current or both, is

discontinued. I A

It will be seen from the foregoing that when the drawbridge C is closed and locked, both track circuit current and train governing current are supplied to the section A E sect whereas when the drawbridge G is rinlo \Cl the supply of both track circuit entrant and train governing current is discontinued from the entrance end A to the drawbridge C; track circuit current however, is supplied to the rails from the drawbridge to the exit end B, and since relay X is de-energized train governing current is also supplied to this portion of the section. It follows that if drawbridge C is unlocked while a train is between this drawbridge and the exit end B, such train will receive a proceed or a caution indication according to the condition of relay R although, of course, a train located between point A and the drawbridge C Will receive a stop indication. In other Words, the drawhridge' Cinay be unlocked and opened after a train has passed this draw bridge and is still in the section AB Without stopping the train.

Although I have herein shown and de-. scribed only one form of apparatus embodying'my invention, it is understood that various changes and modifications may he made therein within the scope ot't'he appended claims without departing from the spirit and scope of my invention.

Having thus described my invention what I claim is: I

1. In combination, a section of railway point to the exit end of said section and a backcontact of said relay.

2. In combination, a section of railway track, a drawloridge located at an intermediate point in said section, three impedances connected across the rails of said section at the entrance end and immediately in advance of said drawbridge and at the exit end respectively. a source of train governing current having one terminal connected with said third impedance and its second terminal connected with said first impedance through the winding of a relay and 21 normally closed contact which is opened when the drawbridge is, open, and means including a back contact of said relay for connecting the second terminal of said source with said third impedance. 7

In testimony whereof I affix my signature.

f 'IRYONALD A. MGCANN; 

